1. Field of the Invention
The present invention relates to a dispenser apparatus, and more particularly relates to a structure of a dispenser apparatus which can introduce an accurate amount of highly viscous liquid into a prescribed portion within a prescribed time.
2. Description of the Background Art
Conventionally, when one member is fixed to the other member having a threaded hole formed therein using a screw, an anaerobic sealing agent is occasionally used for locking the screw in the threaded hole in advance. The technique is hereinafter described referring to FIGS. 5 and 6. FIG. 5 is a plan view of the member, and FIG. 6 is a cross section of the member in FIG. 5 viewed in the direction of the arrow.
Referring to FIG. 5, when threaded holes 52 are formed in the four corners of a member 50, for example, a prescribed amount of an anaerobic sealing agent 1 is automatically injected into threaded hole 52 using a dispenser apparatus. Referring to FIG. 6, when a screw 53 is tightened in threaded hole 52 in which anaerobic sealing agent 1 is injected, anaerobic sealing agent 1 fills a gap between screw 53 and threaded hole 52 and seals them. Anaerobic sealing agent 1 thereafter sets, and screw 53 is fixedly attached to threaded hole 52 so that a member 54 is fastened to member 50 by screw 53.
When a prescribed amount of anaerobic sealing agent 1 having high viscosity is injected, a dispenser apparatus 100 shown in FIG. 7 is utilized. A structure of dispenser apparatus 100 is briefly described below.
A cylinder 10 constituted by a cylindrical body having an inject portion 10a for anaerobic sealing agent 1 at its front end side and an opening 10c at its rear end side is attached to dispenser unit 100. A piston 10b is provided movably between the front and rear end sides of cylinder 10 for defining a space inside cylinder 10 in which anaerobic sealing agent 1 is enclosed.
In the condition shown in FIG. 7, the inside of cylinder 10 is filled with anaerobic sealing agent 1. A plunger 104 is connected to piston 10b for driving piston 10b provided to dispenser apparatus 100.
Considering the effective use of the anaerobic sealing agent and the efficient operation, the most important thing for cylinder 10 having the structure above in the introduction of anaerobic sealing agent 1 is that a prescribed amount of anaerobic sealing agent 1 is accurately injected within a prescribed time. If the injected amount of anaerobic sealing agent 1 is small, for example, the agent would not function as a locking agent for a screw. On the other hand, if the injected amount of anaerobic sealing agent 1 is large, anaerobic sealing agent 1 overflows from the threaded hole, and removal of the overflow of anaerobic sealing agent 1 is required.
When anaerobic sealing agent 1 is pushed to the front end side following the movement of piston 10b, a high pressure is applied to anaerobic sealing agent 1 within cylinder 10 since the inner diameter of cylinder 10 and that of inject portion 10a are widely different from each other. The higher the viscosity of the agent, the higher the pressure applied to anaerobic sealing agent 1. Accordingly, cylinder 10 is caused to expand greatly. Although the expansion of the cylinder 10 can be avoided by forming cylinder 10 from a member having a high rigidity, cylinder 10 is generally produced from a disposable member which is mass-produced in the market. Considering the cost of cylinder 10, a member which inevitably causes any expansion is utilized for cylinder 10.
As a result, when piston 10b is moved by a prescribed distance for introducing a prescribed amount of anaerobic sealing agent 1 into threaded hole 52, an amount of anaerobic sealing agent 1 exceeding a prescribed amount thereof continue to flow from the front end of inject portion 10a still after a prescribed time elapses due to the pressure applied from cylinder 10 to anaerobic sealing agent 1 after cylinder 10 expands. Accordingly, a problem of increase in the amount of the anaerobic sealing agent to be used and decrease in the operating efficiency occurs.